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Zhaoqi Guo, Yunlong Wu, Chongqing Deng, Guoping Yang, Jiangong Zhang, Zhihua Sun, Haixia Ma, Chao Gao, Zhongwei An
Two new energetic coordination polymers (CPs) [Pb(BT)(H2O)3]n (1) and [Pb3(DOBT)3(H2O)2]n·(4H2O)n (2) with 1D and 3D structures were synthesized by employing two rational designed ligands, 1H,1'H-5,5'-bitetrazole (H2BT) and 1H,1'H-[5,5'-bitetrazole]-1,1'-diol ligands (DHBT), respectively. Thermal analyses and sensitivity tests show that the 3D architecture reinforces the network of 2 which has higher thermal stability and lower sensitivity than that of 1. Through oxygen-bomb combustion calorimetry the molar enthalpy of formation of 2 is derived to be much higher than that of 1 as well as the reported CPs...
October 26, 2016: Inorganic Chemistry
Mengjun Tang, Xiaowen Sun, Shan Zhang, Juan Wan, Lin Li, Hong Ni
AIMS: The cell-surface display of chitinase Chi9602ΔSP was constructed on B. thuringiensis BMB171 by using two repeat N-terminal regions of autolysin (Mbgn)2 as the anchoring motif. This study aimed to prepare a chitinolytic whole-cell B. thuringiensis biocatalyst with improved catalytic and antifungal activities. METHODS AND RESULTS: The chitinase Chi9602ΔSP was displayed on the cell surface of B. thuringiensis BMB171 by using (Mbgn)2 as the anchoring motif. Immunofluorescence microscopic assays and flow cytometry confirmed that Chi9602ΔSP was anchored onto the surface of vegetative cells and spores...
October 26, 2016: Journal of Applied Microbiology
Se Hyeon Park, Feilicia Soetyono, Hyung Kwoun Kim
Lysine decarboxylase (CadA) converts L-lysine into cadaverine (1,5-pentanediamin), which is an important platform chemical with many industrial applications. Although there have been many efforts to produce cadaverine through the soluble CadA enzyme or Escherichia coli whole cells overexpressing the CadA enzyme, there have been few reports concerning the immobilization of the CadA enzyme. Here, we have prepared a cross-linked enzyme aggregate (CLEA) of E. coli CadA and performed bioconversion using CadA(CLEA)...
October 25, 2016: Journal of Microbiology and Biotechnology
Woo Soo Jeong, Dong Ho Seo, Jong Hyun Jung, Dong Hyun Jung, Dong-Woo Lee, Young-Seo Park, Cheonseok Park
A highly thermostable β-(1-4)-glucanase (NA23_08975) gene (fig) from Fervidobacterium islandicum AW-1, a native-feather degrading thermophilic eubacterium, was cloned and expressed in Escherichia coli. The recombinant FiG (rFiG) protein showed strong activity toward β-D-glucan from barley (367.0 IU/mg), galactomannan (174.0 IU/mg), and 4-nitrophenyl-cellobioside (pNPC, 66.1 IU/mg), but relatively weak activity was observed with hydroxyethyl cellulose (HEC, 5.3 IU/mg), carboxymethyl cellulose (CMC, 2.4 IU/mg), and xylan from oat spelt (1...
October 25, 2016: Journal of Microbiology and Biotechnology
Castrese Morrone, Riccardo Miggiano, Mario Serpe, Alberto Massarotti, Anna Valenti, Giovanni Del Monaco, Mosè Rossi, Franca Rossi, Menico Rizzi, Giuseppe Perugino, Maria Ciaramella
BACKGROUND: Alkylated DNA-protein alkyltransferases (AGTs) are conserved proteins that repair alkylation damage in DNA by using a single-step mechanism leading to irreversible alkylation of the catalytic cysteine in the active site. Trans-alkylation induces inactivation and destabilization of the protein, both in vitro and in vivo, likely triggering conformational changes. A complete picture of structural rearrangements occurring during the reaction cycle is missing, despite considerable interest raised by the peculiarity of AGT reaction, and the contribution of a functional AGT in limiting the efficacy of chemotherapy with alkylating drugs...
October 21, 2016: Biochimica et Biophysica Acta
Poonam Syal, Rani Gupta
Five lipase genes, ylip4, ylip5, ylip7, ylip13 and ylip15, from Yarrowia lipolytica MSR80 were cloned and expressed in pEZZ18-HB101 system. The lipases shared maximum sequence identity with Candida galli lipase, while they shared structural similarity with YLIP2 of Y. lipolytica CLIB122. The enzymes, purified using IgG Sepharose, had specific activities in the range of 7-25 U/mg. Biochemical characteristics of all the lipases varied with respect to thermostability, substrate specificity and enantioselectivity...
October 24, 2016: Biotechnology and Applied Biochemistry
Shengnan Yin, Yiran Xia, Qi Jia, Zhao-Sheng Hou, Na Zhang
This study describes the preparation and properties of a novel aliphatic cost-effective segmented polyurethanes (SPUs) based on poly(ether ester) (poly-(ε-caprolactone-co-L-lactide)-poly(ethylene glycol)-poly-(ε-caprolactone-co-L- lactide), PECLA) and uniform-size diurethane diisocyanates (HDI-BDO-HDI). PECLA was synthesized via bulk ring-opening polymerization with poly(ethylene glycol) (PEG) as an initiator and ε-caprolactone, L-lactide as monomers. By chain extension of PECLA diol with HDI-BDO-HDI, three SPUs with different hydrophilic segments content and hard segments content were obtained...
October 23, 2016: Journal of Biomaterials Science. Polymer Edition
Jianfang Li, Chunjuan Wang, Die Hu, Fengjiao Yuan, Xueqing Li, Shihan Tang, Minchen Wu
A family 27 carbohydrate-binding module of a Thermotoga maritima β-mannanase (TmCBM27) was chosen from the carbohydrate-active enzyme database by computer-aided design, possessing the lowest binding free energy with mannopentaose. To improve the enzymatic properties of a glycoside hydrolase family 5 β-mannanase from Aspergillus usamii (AuMan5A), two fusion β-mannanases, AuMan5A-F-M and AuMan5A-R-M, were designed by fusing a TmCBM27 into its C-terminus linked with a flexible peptide F (GGGGS)3 and rigid peptide R (EAAAK)3...
October 20, 2016: Journal of Bioscience and Bioengineering
Sandeep Kumar, Kavish Kr Jain, Shikha Rani, Kailash N Bhardwaj, Manisha Goel, Ramesh Chander Kuhad
Among lignocellulolytic enzymes, laccases are the most versatile, broadly specific, and largely studied enzyme with a wide range of biotechnological potential. Putative laccase (CotA) from Bacillus pumilus MK001 was cloned and expressed in E. coli. In addition to soluble bioactive fraction, inactive inclusion body fraction was also harvested and refolded under optimized conditions resulting in 64 % of refolding efficiency. The enzyme was found to be thermostable exhibiting a half-life of 60 min at 80 °C...
October 22, 2016: Molecular Biotechnology
Andrew J Loder, Yejun Han, Aaron B Hawkins, Hong Lian, Gina L Lipscomb, Gerrit J Schut, Matthew W Keller, Michael W W Adams, Robert M Kelly
The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle fixes CO2 in extremely thermoacidophilic archaea and holds promise for metabolic engineering because of its thermostability and potentially rapid pathway kinetics. A reaction kinetics model was developed to examine the biological and biotechnological attributes of the 3HP/4HB cycle as it operates in Metallosphaera sedula, based on previous information as well as on kinetic parameters determined here for recombinant versions of five of the cycle enzymes (malonyl-CoA/succinyl-CoA reductase, 3-hydroxypropionyl-CoA synthetase, 3-hydroxypropionyl-CoA dehydratase, acryloyl-CoA reductase, and succinic semialdehyde reductase)...
October 19, 2016: Metabolic Engineering
Gaurav Kumar Pal, P V Suresh
Collagen and collagen fibers have been widely documented as a potential and competitive biomaterial for medical applications. However, the searches for safe and realistic new collagen sources are still underway. Currently, fishery by-products (scales), a promising collagen source are usually discarded. In the present study, in vitro fibril-forming ability of the extracted fish scale collagen is reported. The aim of the investigation was to evaluate the concomitant comparison of fibril-forming abilities and characteristics of acid and pepsin soluble collagens from the scales of Indian major carp catla (Catla catla) and rohu (Labeo rohita)...
January 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Shiping Liu, Shaojun Ding
BACKGROUND: Acetylation of the xylan backbone was a major obstacle to enzymatic decomposition. Removal of acetyl groups by acetyl xylan esterases (AXEs) is essential for completely enzymatic hydrolysis of xylan. Appended carbohydrate binding modules (CBMs) can promote the enzymatic deconstruction of plant cell walls by targeting and proximity effects. Fungal acetyl xylan esterases are strictly appended to cellulose-specific CBM1. It is still unclear whether xylan-specific CBMs have a greater advantage than CBM1 in potentiating the activity of fungal deacetylating enzymes and its synergistic hydrolysis of different substrates with xylanase...
October 22, 2016: BMC Biotechnology
Elena Sugrue, Paul D Carr, Colin Scott, Colin J Jackson
The desolvation of ionizable residues in the active sites of enzymes and the subsequent effects on catalysis and thermostability have been studied in model systems, yet little is known regarding how enzymes can naturally evolve active sites with highly reactive and desolvated charges. Variants of triazine hydrolase (TrzN) with significant differences in their active sites have been isolated from different bacterial strains: TrzN from Nocardioides sp. strain MTD22 contains a catalytic glutamate residue (Glu241) that is surrounded by hydrophobic and aromatic second-shell residues (Pro214, Tyr215), whereas TrzN from Nocardioides sp...
October 21, 2016: Biochemistry
I Caglar Tanrikulu, Audrey Forticaux, Song Jin, Ronald T Raines
Sticky-ended DNA duplexes can associate spontaneously into long double helices; however, such self-assembly is much less developed with proteins. Collagen is the most prevalent component of the extracellular matrix and a common clinical biomaterial. As for natural DNA, the ~10(3)-residue triple helices (~300 nm) of natural collagen are recalcitrant to chemical synthesis. Here we show how the self-assembly of short collagen-mimetic peptides (CMPs) can enable the fabrication of synthetic collagen triple helices that are nearly a micrometre in length...
November 2016: Nature Chemistry
Samiha Mhamdi, Naourez Ktari, Sawssen Hajji, Moncef Nasri, Alya Sellami Kamoun
The present study was undertaken to characterize the extracellular thermostable serine alkaline proteases from newly actinomycete strain Micromonospora chaiyaphumensis S103 and to describe their evaluation in commercial detergents and shrimp waste deproteinization. This proteolytic crude extract was active and stable in alkaline solution. It was extremely stable in the pH range of 5.0-12.0. The optimum pH and temperature were 8.0 and 70°C, respectively, using casein as a substrate. The thermoactivity and thermostability of proteases were enhanced by the addition of 5mM Ca(2+)...
October 17, 2016: International Journal of Biological Macromolecules
Folasade M Olajuyigbe, Cornelius O Fatokun
Functionality of enzymes within narrow pH range and temperature is a major challenge which limits their industrial applications, hence, there is need to search for thermostable pH-versatile enzymes. Here, a novel thermostable pH-versatile laccase from Sporothrix carnis CPF-05 was purified by ion-exchange and gel filtration chromatography. Single protein band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) confirmed homogeneity of the enzyme with molecular weight of 56kDa. Enzyme yield was 3...
October 17, 2016: International Journal of Biological Macromolecules
Jong Min Lee, Soo Young Moon, Yu-Ri Kim, Kang Woong Kim, Bong-Joo Lee, In-Soo Kong
The aim of this study was to improve the stability of β-1,3-1,4-glucanase by substituting hydrophobic residue for specific amino acid. The results indicated that the catalytic efficiency, thermostability and halostability were enhanced simultaneously by replacement of Lys48 with Ala (K48A) or Leu (K48L). Comparison of kinetic parameters revealed that catalytic efficiency of mutants is enhanced as a result of the increase in substrate affinity. A great improvement in thermostability and halostability was observed...
October 17, 2016: International Journal of Biological Macromolecules
Andrea Tarallo, Maria Cristina Gambi, Giuseppe D'Onofrio
A comparative analysis of polychaete species, classified as motile and low-motile forms, highlighted that the former were characterized not only by a higher metabolic rate (MR), but also by a higher genomic GC content. The fluctuation of both variables was not affected by the phylogenetic relationship of the species. Thus, present results further support that a very active lifestyle affects at the same time MR and GC, showing an unexpected similarity between invertebrates and vertebrates. In teleost, indeed, a similar pattern has been also observed comparing migratory and non-migratory species...
October 7, 2016: Physiological Genomics
Meihui Chang, Xiaoyu Chu, Jinzhi Lv, Qingbin Li, Jian Tian, Ningfeng Wu
Pullulanase (EC plays an important role in the specific hydrolysis of branch points in amylopectin. Enhancing its thermostability is required for its industrial application. In this study, rational protein design was used to improve the thermostability of PulB from Bacillus naganoensis (AB231790.1), which has strong enzymatic properties. Three positive single-site mutants (PulB-D328H, PulB-N387D, and PulB-A414P) were selected from six mutants. After incubation at 65°C for 5 min, the residual activities of PulB-D328H, PulB-N387D, and PulB-A414P were 4...
2016: PloS One
Hee Jin Lee, In Jung Kim, Hak Jin Youn, Eun Ju Yun, In-Geol Choi, Kyoung Heon Kim
Processivity is a typical characteristic of cellobiohydrolases (CBHs); it enables the enzyme to successively hydrolyze the ends of cellulose chains and to produce cellobiose as the major product. Some microbes, which do not have CBHs, utilize endoglucanases (EGs) that exhibit processivity, commonly referred to as processive EGs. A processive EG identified from Hahella chejuensis, HcCel5, has a catalytic domain (CD) belonging to the glycoside hydrolase family 5 (GH5) and two carbohydrate-binding modules (CBM6s)...
October 19, 2016: Bioprocess and Biosystems Engineering
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